2. Model Authorities and Model Exchange
Jay Britton
Principal Architect

3. Model Exchange Business Goal
Neighboring parties in an interconnect exchange models.
Each party is the “modeling authority” only for its own territory.
Each party will use other parties’ internal models to create their external model.
To accomplish this,
Each party exports its internal model to its neighbors and keeps it up to date.
Each party imports each neighbor’s model and uses it to develop and update its external model.
Proposed Goal: an external model can be updated within an hour of a change to a neighbor’s internal.

4. Initial CIM Model Exchange Concept
CIM Exchange
(full, partial, incremental)
CIM import / export
CIM import / export
System B Import Model
System A Import Model a
Proprietary / Home grown
Extract / Merge Tools
Proprietary / Home grown
Extract / Merge Tools b
A Internal Model
B’s Model of A
System A Local Vendor Model
System B Local Vendor Model
A’s model of B
B Internal Model
System B EMS
System A EMS

5. Making CIM Exchange a Complete Process
MRIDs as permanent unique object identifiers.
Decide who assigns identifiers to each object.
Name registry manages naming differences.
Model exchange uses consistent identifiers.
Specify the modeling territories precisely within the model.
Include security against changes submitted by unauthorized parties.
Report updates with CIM incremental updates.
If problems arise, it is easy to identify the source.
Mark equivalents in the model.
Import process can easily recognize whether an update requires a new reduction.
On-line systems receive and test updates incrementally.
If problems arise, it is easy to identify the source

6. Central Concept: Model Authority Sets (MAS)
Notation:
Nodes represent individual CIM objects.
Branches represent relations between objects.
Two MAS types:
Regional (single authority)
Boundary (bipartisan authority / single caretaker)
Rules:
Every CIM object is in one and only one MAS.
Each MAS controls object MRIDs in its territory.
No object in a regional set relates directly to any object in another regional set.

7. A little more detailed look at a boundary example.

8. A UCTE boundary example.

9. Use Case: Peer-to-Peer Full Model Exchange
CIM Modeler
CIM Modeler
A Region
A Region
boundary
boundary
B Region
B Region a
A Region (reduced)
B Region (reduced) b
System A
EMS
System B
EMS
CIM import
CIM import
Proprietary
Model B
Proprietary
Model A

10. Use Case: A to B Incremental Update
CIM Modeler
CIM Modeler a a
A Region
A Region
boundary
boundary
B Region
B Region
A Region (reduced)
B Region (reduced)
If the change can be processed against the reduced region, then it can be transferred directly to the CIM import for system B.
System A
Local Vendor
System B
Local Vendor
CIM delta
CIM MAS
CIM delta
Proprietary
Model B
Proprietary
Model A

11. Use Case: Hierarchical Exchange
CIM Upper Tier Modeling x
A Region
boundary
B Region
CIM Region Modeling
CIM Region Modeling
A Region
A Region
boundary
boundary
B Region
B Region a b
A Region (reduced)
B Region (reduced)
CIM import
CIM import
System A Local Vendor
System B Local Vendor
Proprietary
Model A
Proprietary
Model B

12. Why is this a good thing? Generality
MAS delineate all objects, not just the physical connection boundaries.
Establishing authority and responsibility…
Basis for efficient, repeatable processes.
Clarifies responsibility for naming and MRIDs for all objects.
Processing efficiency for model exchange:
Merging regions is a simple union of objects.
Extraction is a simple transfer of objects without modification.
Replace simply extracts and discards before merging.
Maximum XML file size can be limited to maximum largest MAS size, rather than whole interconnect.
Checking that a change comes from the correct source.
As a regional MA submitting a change:
You can make any change you want to your regional set without fear that it would disturb a relationship from another region.
Your changes can easily be validated because they must be referentially complete without any other regional set.
If your change cannot comply with the above condition, it tells you immediately that you need to arbitrate a change in a boundary set.
As the receiver checking the right to make a change:
It must be referentially complete against the source’s region plus its boundaries.